Machine for forming threads on metal tubing



March 31, 1936. T. BRIEGEL 2,035,687

} MACHINE FOR FORMING THREADS ON METAL TUBING Filed Dec. 24, 1954 FIE-1FIE E X 20- 30 28 I3 22 2e 15 3 17 29 FIE'E! INVENTOR.

Mu /1L BY 94%, Am

i k ATTORNEY.

Patented Mar. 31, 1936 UNITED STATES PATENT OFFICE MACHINE FOR FORMINGTHREADS ON IWETAL TUBING 8 Claims.

My invention has reference to a machine for forming threads on metaltubing, and relates more specially to operations of that nature on whatis known as fixture brass tubing, and other thin wall tubing of thatcharacter. Great difficulty is encountered in cutting a screw thread ona piece of tubing of the kind named on account of the tubing beingprovided with a high finish, such as nickel or chromium, which is liableto be damaged by holding the tubing in a vise or other gripping device.There is also danger of jamming or bending the tubing, on account of itscomparative light weight. By means of said invention the necessity ofgripping the tubing in any way is entirely done away with.

It is sometimes necessary or desirable to cut fresh threads on the endof a tube already estab lished in a wall or other part of a building,and this can be easily. done by the use of said invention, and on apiece of tubing which projects only a fractional part of an inch fromthe wall. It is a convenient plumbers tool, for work on the job underall conditions.

The device includes a hand-operated tool, which includes athread-cutting apparatus, the suporting shaft for which is engageablewith the end of a section of tubing from the inside thereof while thethread forming operation is proceeding. Nipples and other short piecesof tubing can also be positioned thereon and provided with a thread. Thedies in the thread-cutting apparatus are interchangeable for use withsections of tubing of difierent diameters, and other parts of themachine are also interchangeable to conform therewith.

The above-named, and other features and advantages of the invention willmore fully appear from the following specification taken in connection'with the accompanying drawing, in which:-

Fig. 1 shows the invention in side view.

Fig. 2 is a longitudinal medial section thereof.

Fig. 3 shows a modified form of the expansion devices, detached.

Fig. 4 is adetail of a washer 33, in position on the shaft 5.

The reference number 5 indicates a spindle or shaft, reduced at one endinto a threaded pin 6, on which is seated a nut l. Held in place on saidshaft by the nut is a taper member 8, provided at its inner end with anotch 9, engaged by a pin H! fixed in said shaft. By this means themovement of the part 8 inwardly is limited, and said part is alsorotatable with the shaft, or held from rotation therewith. On theoutside of the member 8 is an expansion mandrel ll, provided in itswalls with alternately oppositely disposed slots I 2, lending a dgree ofresiliency thereto. The inner wall of the mandrel is tapered to coincidewith the taper of the part 8, and the outer 5 wall of said mandrel isconcentric with the shaft 5, and adapted to receive the end of a sectionof tubing, as indicated at l3 in Fig. 2. Upon the mandrel H being forcedupon the member 8 the walls of the mandrel are spread, until the 10inner wall of'the tubing is engaged thereby, and held rigidly connectedtherewith. The member 8 is also provided with a pin l5, entering one ofthe slots l2 in the mandrel, and holding the same from accidentalrelease from the taper member. 1

Slidable on the shaft 5 is a sleeve I6, provided on its outer wall witha thread I1, engagedv by a similar thread in the bore of a hub l8,projected from a die-mounting 19, in which is secured a die-ring 20.Openings 2| are providedin said mounting, by means of which it can berotated on the sleeve l6, for a gradual feed thereof when in operation.The shaft 5 is also provided with a key-way 22, in which is movable akey 23, fixed in the sleeve l6, whereby said sleeve'is caused to rotatewith the shaft, or is held from turning therewith when the shaft isstationary.

At the. opposite end of the shaft 5 from the expansion devices is ascrew thread 25, on the end of which is fixed a collar 26, connectedwith a head 21, provided with a lateral bore 28, for use with a rod orother tool when it is desired to hold the shaft from turning. There isalso mounted on said thread a travelling nut 29, provided with openings30 for use with a tool, in turning said nut. When the nut is turned tomove inwardly on the shaft 5 it comes in contact with the inner end ofthe sleeve [6, and a continued rotation thereof brings said sleeve intocontact with the inner end of the mandrel II, which is thereby movedoutwardly, with the expansion effect hereinbefore described. Thefrictional engagement of the nut with the end of the sleeve It alsoserves to lock said parts from release.

The threads on the sleeve l6 are of finer pitch than those on the shaft5, and are similar to those of the thread cutting dies. The length ofthe thread on said sleeve is such that threads can 0 be cut on a pieceof tubing as far as the end of the shaft 5 extends into the same.

When a thread is to be cut on the end of a piece of tubing, such tubingis supported on a bench or other support without any clamping or 55gripping means, and the end of the shaft 5, with the expansion devicesthereon in non-expanded position, inserted in the end of the tubing. Theshaft is then held from turning by means of the head 21, and the nut 29rotated to actuate the sleeve 15, and cause the expansion operation atthe outer end thereof. When the mandrel is rigidly engaged with theinner wall of the tubing the die-mounting I9 is turned until the threadsin the die 20 engage the end of the tubing, and a continued rotation ofthe die serves to produce a thread on the end of the tubing for thedesired distance. The same rod or bar can be employed for turning thedie-holder that is used for the nut 29. In the threading operation thepiece of tubing, of whatever length, is held from turning by means ofthe shaft 5 anchored therein, and there is no need of holding the tubingin a vise or other clamping means. There is therefore no necessity formarring or otherwise injuring the finish on the outer wall of thetubing, or of distorting the same by gripping devices attached'thereto,as is now the case.

At 3| is shown a ring section of tubing, such as are used for nipples,in position on the mandrel I I. When thus held in rigid position threadscan be cut thereon as before described. Short sections of tubing can besimilarly threaded. In case a piece of tubing projects a little waysbeyond a wall, as indicated by the line a:-x of Fig. 2, the end of thetool can be secured in place in the tube in the manner described, andthe threadcutting operation carried on, with the dies operating on thetubing to a point close to the wall. In this way a piece of tubingprojecting'a halfinch or less from a fixture can be provided with athread on its outer surface, for use with a nut or other connections,and without disturbing the tubing or wall in any way.

When it is desired to release the tool from a piece of tubing, the nut29 is moved along the shaft 5 away from the sleeve l6, and a sharp blowgiven to the outer face of the head 21, tending to separate the member 8and mandrel II, and loosen the same from the tubing. It is not necessaryto have the end of the tubingsupported on the mandrel for the fulllength of such mandrel, as the insertion thereof into the tubing for ashort distance only will serve to support the tubing sufiiciently, afterthe mandrel has been expanded and clamped in position.

There is shown interposed between the outer end of the casing l6 andmandrel H a washer 33, provided with a notch 34, by means whereof it canbe slipped over the pin III. In some cases the diameter of the bore ofthe mandrel ll may be greater than that of the sleeve [6, so that theywill fail to contact, but by use of a washer 33 of suflicient outerdiameter this defect can be remedied. The diameters of thin wall tubingof the kind mentioned vary from one inch to two inch, with variations ofone-eighth inch between said sizes, and taper members and mandrels ofgreater size can also be used, as shown in Fig. 3, When it is desired tochange the expansion tools the nut I is removed, and the member 8slipped off the end of the shaft 5, with the mandrel connectedtherewith. Another taper member and mandrel therefor are thensubstituted for the ones removed. Dies with cutting diameters conformingto the various sizes of tubing are also used interchangeably in themounting I9. Washers 33 of greater diameters will also have to be usedwith the larger sizes of tubing.

The tool can also be used for cutting threads on tubing of extra largesizes or on sizes less" than those mentioned, by forming the tool ofcorrespondingly larger or smaller dimensions.

The outer wall of the mandrel is parallel with the wall of the tubing,and it will be noted that when the expansion elements are firmly engagedin the end of a piece of tubing, they provide an anchorage therein forthe tool, the other end of which can be supported by the operator. Inturning the nut 29 in a direction to expand the mandrel it is thepractice to hold the head 2'! from rotation with one hand and turn thenut 21 with the other, or with a tool used for that purpose. In thethread cutting operation the head 21 can still be held by one hand andthe threading tool turned by the other. In these operations, the samebar or rod can be used for turning the nut 29 and mounting I9.

Other changes and variations in the construction and arrangement of thetool can be made besides those noted herein, without departing from thescope of the invention.

What I claim, and desire to secure by Letters Patent, is:

.1. A thread cutting tool, comprising a shaft, expansion devicesconnected with said shaft so as to be non-rotatable therewith, a tubularmember slidable on said shaft and non-rotatable therewith, a die-holderrotatably mounted on said tubular member, means for holding said tubularmember in fixed position, and coacting means on said tubular member anddie-holder for suitably feeding the die-holder towards its work duringthe rotation thereof.

2. A thread cutting tool, comprising a shaft, expansion devices on oneend of said shaft engageable with the inner wall of a tubular section, atubular member slidable on said shaft and engageable with said expansiondevices to cause an expansion thereof, means on said shaft for actuatingsaid tubular member, means for holding said shaft from rotation, adie-mounting rotatably supported on said tubular member, and threadedconnections between said tubular member and die-mounting for giving adesired feed movement to the die-mounting during its rotation.

3. A thread cutting tool, comprising a shaft provided at one of its endswith a screw thread, expansion devices non-rotatable therewith, andadapted for engagement with the inner wall of a piece of tubing, atubular member slidable on said shaft-and nonrotatable therewith,engageable with said expansion devices to actuate the same, a travelingnut .on said screw thread, engageable with said tubular member for theoperation thereof, a diemounting on said tubular member, having athreaded feed connection with said member, and means for holding saidshaft from rotation.

4. A thread cutting tool, comprising a shaft provided at one of its endswith a screw thread, expansion devices on the other end of said shaft,engageable with the inner wall of a piece of tubing, a tubular memberslidable on said shaft and non-rotatable therewith, engageable with saidexpansion devices to cause the expansion thereof, a traveling nut onsaid screw thread, engageable with said tubular member to cause anexpansion action thereof, and lock the same therein, a die-mountingsupported rotatably on said tubular member, threaded connections betweensaid die-holder and tubular member to cause the feed of saiddie-mounting toward its work, and

on the other end of said shaft,

means for holding said shaft from rotation during the movement of saidtraveling nut and of said die-mounting.

5. In a device of the class described, a shaft, a taper member connectedwith said shaft and non-rotatable therewith, an expansible sleeve onsaid taper member, expansible by a longitudinal movement thereon, amember slidable on said shaft and non-rotatable therewith, engageablewith said expansible sleeve to cause an expansion thereof, means on saidshaft for actuating said slidable member and holding the same inengaging position, a threading tool rotatably mounted on said last-namedmember, and having a threaded connection therewith for feed action, andmeans for holding said shaft from rotation.

6. In a device of the class described, a shaft, an expansion deviceconnected with said shaft, and non-rotatable therewith, a tubular memberslidable on said shaft, non-rotatable therewith, engageable with saidexpansion device to actuate the same, and provided on its outer wallwith a feed-thread similar to the thread to be cut on a piece of tubing,a die-mounting threaded for engagement with said feed-thread, athreading die detachably connected with said die-mounting, forinterchanging with similar dies, means on said shaft for actuating saidtubular member, and means for holding said shaft from rotation.

7. In a device of the class described, a shaft, a taper member connecteddetachably with said shaft, non-rotatable therewith, an expansion sleeveon said taper member, a tubular member engageable with said sleeve toexpand the same, non-rotatable with said shaft, and provided on itsouter wall with a feed thread, a threading tool rotatably mounted onsaid tubular member, provided with a thread for engagement with saidfeed thread, a threading die held removably in said threading tool,means on said shaft for the operation of said tubular member, and meansfor holding said shaft from rotation.

8. In a thread cutting tool, a shaft provided at one of its ends with ascrew thread, an expansion device on the other end of said shaft, asleeve slidable on said shaft and non-rotatable therewith, a travellingnut on said screw thread engageable with said sleeve to move it towardsaid expansion device, a collar interposed between said sleeve and saidexpansion device of greater diameter than the end of said sleeve, athread cutting tool mounted rotatably on said sleeve, thread connectionsbetween said thread cutting tool and said sleeve, for suitable feedmovement of said tool, and means for holding said shaft from rotation.

THEODORE BRIEGEL.

